There are plenty of reasons why other devs would listen to Valve and support this project, not the least of which being to escape the closed App Store model.

See, here's the thing you people aren't understanding... When you made a Windows program before, Microsoft couldn't prevent someone else from installing it. Same with Apple computers. That's changed now, and both Microsoft and Apple are using their muscle to rig new computers so that you've got OS lock-in, AND can only install applications from their app store.

When you develop for SteamOS, you're really developing for Linux, with some Steam API stuff on the side. Ditching SteamOS and making a generic Lunix binary and distributing it is trivial compared to working around a closed proprietary platform, like Windows 8 RT or Maverick.

You don't understand what SteamOS is about. It's not about SteamOS becoming a dominant OS, it's about enhancing Linux support by making Linux gaming accessible to more people with less effort, making a bigger potential market for hardware makers to give proper driver support, so that nobody besides Valve can block what gets onto Valve's game distribution platform, so Valve can make more money. As this happens, though, there's no way for Valve to prevent game developers from releasing on Linux, but outside of Valve's Steam platform. That's why developers are not afraid of lockin.